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KMID : 1059519930370030344
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Journal of the Korean Chemical Society
1993 Volume.37 No. 3 p.344 ~ p.350
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The Crystal and Molecular Structure of 25,26,27,28-Tetrnacetoxy[4]Arene·Monohydrate
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Ahn Choong-Tai
No Kwang-Hyun
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Abstract
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25,26,27,28-Tetraacetoxycalix[4]arene·monohydrate is orthorhombic, space group Pbca with a = 14.979(4), b = 15.154(4), c = 27.890(3) Å, Z = 8, V = 6330.6 Å-3, Dc = 1.28 g·cm-3, (Mo Kα) = 0.71069 Å, μ = 0.86 cm-1, F(000) = 2600, and R = 0.069 for 3376 unique observed reflections with I > 1.0 σ(I). The structure was solved by direct methods and refined by cascade diagonal least-squares refinement. All the C-H bond lengths(= 0.96 Å), the methyl groups and the methylene groups are fixed and refined as the rigid groups with ideal geometry. The macrocycle exists in the 1,3 alternate conformation (by Conforth) making the angles of 110.7, 684, 113.7 and 68.8° between the benzene rings and the methylenic mean plane, and four each acetoxy groups are twisted away from their own benzene rings with the angles of 68.2, 97.6, 78.9 and 71.3°, respectively. The relative dihedral angles between two opposite side of the benzene rings are 135.6° for the rings (1) and (3) and 135.2° for (2) and (4). A water molecule which has nearly the same height of the methylenic plane of the macrocycle in the c-axis, is located within the distances of 2.942(5) Å from the O(8) atom of the carbonyl group and 2.901 Å from, another O(2)(1/2-x, -1/2＋y, z). The shortest contact between the molecule is 3.193 Å from the O(4) to the C(3)(1/2＋x, 1/2-y,-z).
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